Method and apparatus of three-dimensional printing and electronic apparatus

ABSTRACT

A method and an apparatus of three-dimensional (3D) printing and an electronic apparatus are provided. The 3D printing method is adapted for printing a 3D object and includes the following. A plurality of layer objects of a 3D model are obtained, and a plurality of two-dimensional images, which correspond to a slice plane, of each of the layer objects are generated. The layer objects include a first layer object and a second layer object. When a comparison relationship between a two-dimensional image of the first layer object and a two-dimensional image of the second layer object matches a stack condition, the first layer object and the second layer object are stacked to generate thickness stack information of a stack object. A printing mechanism is initiated according to the thickness stack information so as to print a 3D object associated with the 3D model.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of Taiwan applicationserial no. 103109897, filed on Mar. 17, 2014. The entirety of theabove-mentioned patent application is hereby incorporated by referenceherein and made a part of this specification.

BACKGROUND

1. Technical Field

The technical field relates to a printing method and more particularlyrelates to a three-dimensional printing method.

2. Description of Related Art

As the technology advanced in recent years, many methods that utilizeadditive manufacturing technology (e.g. layer-by-layer modelconstruction) to build three-dimensional (3D) physical models have beenproposed. Generally speaking, the additive manufacturing technology isto transfer data of the design of a 3D model, which is constructed bysoftware, such as computer aided design (CAD), to multiple thin(quasi-two-dimensional) cross-sectional layers that are stacked insequence. In the meantime, many techniques for forming thincross-sectional layers are also proposed. For example, a printing moduleof a printing apparatus is usually configured to move above a base alongan XY plane according to spatial coordinates XYZ constructed accordingto the design data of the 3D model, so as to use a construction materialto form shapes of the cross-sectional shapes correctly. Then, thedeposited construction material may be cured naturally or by heating orlight irradiation to form the desired cross-sectional layers. By movingthe printing module along the Z axis layer by layer, multiplecross-sectional layers can be gradually stacked along the Z axis, andwhile the construction material is cured layer by layer, a 3D object isformed.

Take the technology that forms 3D objects by curing the constructionmaterial with a light source as an example, the printing module isconfigured to be immersed in a liquid molding material in a container,and a light source module is disposed to irradiate the liquid moldingmaterial that serves as the construction material on the XY plane, so asto cure and stack the liquid molding material on a movable platform ofthe printing module. Accordingly, by moving the movable platform of theprinting module layer by layer along the Z axis, the liquid moldingmaterial can be gradually cured and stacked to form the 3D object.However, for the current 3D printing technology, how to improve 3Dprinting speed and quality is still an important issue.

SUMMARY

One of the exemplary embodiments provides a three-dimensional printingmethod, a three-dimensional printing apparatus, and an electronicapparatus for increasing a speed of three-dimensional printing.

One of exemplary embodiments provides a three-dimensional printingmethod adapted for printing a three-dimensional object. Thethree-dimensional printing method includes the following steps. Aplurality of layer objects of a three-dimensional model are obtained,and a plurality of two-dimensional images, which correspond to a sliceplane, of each of the layer objects are generated. The layer objectsinclude a first layer object and a second layer object adjacent to eachother. When a comparison relationship between the two-dimensional imageof the first layer object and the two-dimensional image of the secondlayer object matches a stack condition, the first layer object and thesecond layer object are stacked to generate thickness stack informationof a stack object. A printing mechanism is initiated according to thethickness stack information so as to print the three-dimensional objectassociated with the three-dimensional model.

One of exemplary embodiments provides a three-dimensional printingapparatus, including a processor. The processor obtains a plurality oflayer objects of a three-dimensional model and generates a plurality oftwo-dimensional images, corresponding to a slice plane, of each of thelayer objects. The layer objects include a first layer object and asecond layer object adjacent to each other. When a comparisonrelationship between the two-dimensional image of the first layer objectand the two-dimensional image of the second layer object matches a stackcondition, the processor stacks the first layer object and the secondlayer object to generate thickness stack information of a stack object.The processor initiates a printing mechanism according to the thicknessstack information so as to print a three-dimensional object of thethree-dimensional model.

One of exemplary embodiments provides an electronic apparatus, includinga processor. The processor obtains a plurality of layer objects of athree-dimensional model and generates a plurality of two-dimensionalimages, corresponding to a slice plane, of each of the layer objects.The layer objects include a first layer object and a second layer objectadjacent to each other. When a comparison relationship between thetwo-dimensional image of the first layer object and the two-dimensionalimage of the second layer object matches a stack condition, theprocessor stacks the first layer object and the second layer object togenerate thickness stack information of a stack object. The processorcontrols the three-dimensional printing apparatus to initiate a printingmechanism according to the thickness stack information, so as to print athree-dimensional object associated with the three-dimensional model.

Based on the above, in the embodiments of the disclosure, coverages ofmultiple layer objects of the object to be printed with respect to theXY plane are compared for stacking layer objects that match the stackcondition, so as to generate the stack object having cumulativethickness. Accordingly, the three-dimensional printing apparatus adjuststhe output intensity of the light source according to the cumulativethickness of the stack object and controls the irradiation pathwayaccording to the combined control code file, so as to cure theirradiated liquid molding material to form the three-dimensional objecton the movable platform. By cumulating the layers before printing, thethree-dimensional printing apparatus reduces the times of moving themovable platform and effectively shortens the time for scanning of thelight source, thereby improving the printing efficiency.

To make the aforementioned and other features and advantages of thedisclosure more comprehensible, several embodiments accompanied withdrawings are described in detail as follows.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the disclosure, and are incorporated in and constitutea part of this specification. The drawings illustrate exemplaryembodiments of the disclosure and, together with the description, serveto explain the principles of the disclosure.

FIG. 1 is a block diagram illustrating a three-dimensional printingsystem according to an exemplary embodiment.

FIG. 2 is a flowchart illustrating a three-dimensional printing methodaccording to an exemplary embodiment.

FIG. 3 is a partial schematic diagram illustrating a three-dimensionalprinting apparatus according to an exemplary embodiment.

FIG. 4 is a flowchart illustrating a three-dimensional printing methodaccording to an exemplary embodiment.

FIG. 5A and FIG. 5B are schematic cross-sectional diagrams illustratinga three-dimensional object according to an exemplary embodiment.

FIG. 6 is a flowchart illustrating a three-dimensional printing methodaccording to an exemplary embodiment.

FIG. 7A and FIG. 7B are schematic cross-sectional diagrams illustratinga three-dimensional object according to an exemplary embodiment.

FIG. 7C is a schematic diagram illustrating obtaining a combined controlcode file according to an exemplary embodiment.

DESCRIPTION OF THE EMBODIMENTS

Exemplary embodiments of the disclosure are explained in detail belowwith reference to the drawings. In addition, wherever possible,identical or similar reference numerals stand for identical or similarelements/components in the drawings and embodiments.

FIG. 1 is a block diagram illustrating a three-dimensional printingsystem according to an exemplary embodiment. With reference to FIG. 1, athree-dimensional (3D) printing system 10 includes a three-dimensional(3D) printing apparatus 100 and an electronic apparatus 200. The 3Dprinting apparatus 100 is coupled to the electronic apparatus 200 andincludes a processor 110. Likewise, the electronic apparatus 200includes a processor 210.

The electronic apparatus 200 is a device having an operation function,such as a computing device, e.g. laptop computer, tablet computer, ordesktop computer, etc., for example. The disclosure is not intended tolimit the types of the electronic apparatus 200. In this embodiment, theprocessor 210 of the electronic apparatus 200 is capable of editing andprocessing a 3D model of a 3D object and transmitting related 3D modelinformation to the 3D printing apparatus 100, for the 3D printingapparatus 100 to print out the 3D object according to the 3D modelinformation. More specifically, the 3D model may be a digital 3D imagefile that is constructed by the electronic apparatus 200 by means ofcomputer-aided design (CAD) or animation modeling software, for example.

The 3D printing apparatus 100 is adapted for printing a 3D objectaccording to the 3D model information transmitted by the electronicapparatus 200. To be more specific, the processor 110 controls eachcomponent of the 3D printing apparatus 100 according to the 3D modelinformation, so as to reiteratively print a molding material on aplatform until the whole 3D object is formed.

The processors 110 and 210 may be a central processing unit (CPU), aprogrammable microprocessor for general or special use, a digital signalprocessor (DSP), a programmable controller, an application specificintegrated circuit (ASIC), a programmable logic device (PLD), othersimilar devices, or a combination of these devices, for example.Nevertheless, the disclosure is not intended to limit the types of theprocessors 110 and 210.

It is noted that coding and calculation are further performed on the 3Dmodel to generate the 3D model information that the 3D printingapparatus 100 reads to execute the printing function. Specifically, theprocessor 210 of the electronic apparatus 200 first performs a slicingprocess on the 3D model to generate a plurality of layer objects of the3D model. Generally, the processor 210 slices the 3D model by sliceplanes with a fixed interval therebetween, so as to obtain sectionprofiles of the layer objects. The interval by which the 3D model issliced may be deemed as the thickness of the layer object. The smallerthe thickness of the layer object is, the higher the formation precisionof the 3D object is, but the formation time is also longer.

Moreover, the processor 210 generates a control code file correspondingto the section profile of each layer object. The control code file isthe 3D model information that the 3D printing apparatus 100 reads toexecute the printing function. In other words, the processor 110 of the3D printing apparatus 100 controls the components in the 3D printingapparatus 100 according to the control code files, so as to form thelayer objects on the platform layer by layer. In an embodiment, thecontrol code file is a G code file, for example.

FIG. 2 is a flowchart illustrating a three-dimensional printing methodaccording to an exemplary embodiment. The method of this embodiment isadapted for the 3D printing system 10 of FIG. 1. Steps of the 3Dprinting method of this embodiment are explained in detail hereinafterwith reference to the components in the 3D printing system 10.

First, in Step S210, the processor 210 obtains a plurality of layerobjects of a 3D model and generates a plurality of two-dimensional (2D)images, corresponding to a slice plane, of each of the layer objects. Asection profile of each layer object can be clearly seen from the 2Dimages. The layer objects at least include a first layer object and asecond layer object that are adjacent to each other. In other words, thefirst layer object and the second layer object may be deemed as any twoadjacent layer objects among the layer objects.

In Step S230, when a comparison relationship between the 2D image of thefirst layer object and the 2D image of the second layer object matches astack condition, the processor 210 stacks the first layer object and thesecond layer object to generate thickness stack information of a stackobject. That is to say, the processor 210 is capable of comparing the 2Dimage of the first layer object with the 2D image of the second layerobject by various image comparison methods. If the comparisonrelationship between the 2D image of the first layer object and the 2Dimage of the second layer object matches the stack condition, the firstlayer object and the second layer object are stacked to form the stackobject. In addition, the processor 110 generates the thickness stackinformation of the stack object according to thickness information andcontrol code files of the first layer object and the second layerobject, for example.

Then, in Step S250, the processor 210 initiates a printing mechanismaccording to the thickness stack information, so as to print the 3Dobject associated with the 3D model. More specifically, the processor210 transmits the thickness stack information of the stack object to the3D printing apparatus 100 for the 3D printing apparatus 100 to print outthe 3D object associated with the 3D model according to the thicknessstack information.

It is noted that, in an embodiment, the processor 210 compares the layerobjects layer by layer in a direction and continues stacking layerobjects that match the stack condition according to a comparison resultto generate at least one stack object. The thickness of the stack objectis determined by the times of stacking. That is to say, throughperforming the above comparison and stacking processes in sequence, the3D model having multiple layer objects is transferred to the 3D modelhaving at least one stack object. Therefore, the slicing of the 3D modelmay be dynamically adjusted according to the method of the exemplaryembodiment, and the 3D printing apparatus 100 can print the 3D objectaccording to the combined thickness corresponding to the stack objectsand the combined control code files.

It is noted that, in the above embodiment, the processor 210 of theelectronic apparatus 200 executes Steps S210 to S250, for example.However, in another embodiment, Steps S210 to S250 may be executed bythe processor 110 of the 3D printing apparatus 100. Specifically, theprocessor 110 may obtain information related to the multiple layerobjects from the electronic apparatus 200 to generate a plurality of 2Dimages, corresponding to a slice plane, of each of the layer objects.Similarly, after the processor 110 generates the thickness stackinformation of the stack object, the processor 110 may control otherprinting components of the 3D printing apparatus 100 to execute theprinting function.

In order to clearly illustrate and explain the operation principle ofthe 3D printing method of the exemplary embodiments, stereolithography(SLA) is described below as an example. FIG. 3 is a partial schematicdiagram illustrating a three-dimensional printing apparatus according toan exemplary embodiment. Referring to FIG. 3, the 3D printing apparatus100 includes the processor 110, a container 120, a movable platform 130,and a light source 140. Here a Cartesian coordinate system is used todescribe the components and their motions. The container 120 is used tocontain a liquid molding material 102, and a portion of the movableplatform 130 is immersed in the liquid molding material 102. The lightsource 140 is adapted to emit light to the liquid molding material 102.

The processor 110 electrically connects the light source 140 and themovable platform 130 for moving the portion of the movable platform 130above the container 120 along a Z axis. In this embodiment, aphotosensitive resin or other suitable light-curable material is used asthe liquid molding material 102. Thus, after being irradiated by thelight of the light source 140, the liquid molding material 102 is cured.

It is worth mentioning that, in an embodiment, the stack condition isset to determine whether a coverage of the 2D image of the second layerobject is larger than or equal to a coverage of the 2D image of thefirst layer object. In other words, when the coverage of the 2D image ofthe second layer object is larger than or equal to the coverage of the2D image of the first layer object, at least one combined thickness andat least one combined control code file are generated by stacking thefirst layer object and the second layer object. Exemplary embodiments ofdifferent stack conditions and stacking methods are given below toexplain the disclosure.

FIG. 4 is a flowchart illustrating a three-dimensional printing methodaccording to an exemplary embodiment. The method of this embodiment isadapted for the 3D printing system of FIG. 1 and the 3D printingapparatus of FIG. 3. Steps of the 3D printing method of this embodimentare explained in detail hereinafter with reference to the components ofthe 3D printing system 10 and the 3D printing apparatus 100.

First, the processor 210 performs a slicing process on a 3D model toobtain M layer objects (Step S401), wherein M is an integer greaterthan 1. Next, the processor 210 generates a plurality of initial controlcode files respectively corresponding to the layer objects (Step S402).In other words, the processor 210 generates the initial control codefile of an i^(th) layer object in sequence, wherein i is an integergreater than 0 and smaller than or equal to M.

For example, when M is equal to 3, it indicates that the processor 210slices the 3D model into three layer objects, which are a first layerobject, a second layer object, and a third layer object. Then, accordingto section profile information of each layer object, the processor 210respectively generates the initial control code file of the first layerobject, the initial control code file of the second layer object, andthe initial control code file of the third layer object.

Thereafter, the electronic apparatus 200 outputs the initial controlcode file of each layer object, e.g. the G code file of each layerobject, to the 3D printing apparatus 100. Accordingly, the processor 110generates 2D images of each layer object according to the initialcontrol code files (Step S403). Simply put, the processor 110 generatesthe 2D images of the i^(th) layer object according to the initialcontrol code file of the i^(th) layer object. The section profile ofeach layer object can be clearly seen from the 2D images.

Next, the processor 110 determines whether a coverage of a 2D image of a(i+1)^(th) layer object is equal to a coverage of the 2D image of thei^(th) layer object (Step S404). That is to say, the processor 110determines whether two layer objects that are adjacent to each othervertically have the same section profile. If it is determinedaffirmative in Step S404, the processor 110 adds the thickness of the(i+1)^(th) layer object to the current cumulative thickness to generatea combined thickness (Step S405). Thereafter, the processor 110determines whether a (i+2)^(th) layer object exists (Step S406). If itis determined affirmative in Step S406, the processor 110 moves on tothe next layer object to make determination (setting i=i+1) (Step S407)and repeats Step S404. It is known from the above that layer objectsthat are adjacent to each other and have the same section profile arestacked to form the stack object. The thickness of the stack object isdetermined by the times of stacking.

On the other hand, if it is determined negative in Step S404, itindicates that the coverage of the 2D image of the (i+1)^(th) layerobject is not equal to the coverage of the 2D image of the i^(th) layerobject. In other words, the processor 110 determines that the adjacenttwo layer objects do not have the same section profile. Therefore, theprocessor 110 adjusts output intensity of the light source according tothe combined thickness of the stack object (Step S408). In thisembodiment, the thicker the combined thickness of the stack object is,the higher the output intensity of the light source is adjusted, so asto cure the stack object having the combined thickness.

Thereafter, the processor 110 sets the combined control code file (StepS409). It is noted that, because the (i+1)^(th) layer object and thei^(th) layer object have the same section profile, the initial controlcode file of the (i+1)^(th) layer object and the initial control codefile of the i^(th) layer object are the same, and the combined controlcode file of the current stack object is also the same as the initialcontrol code file of the i^(th) layer object. Accordingly, the processor110 sets the combined control code file as the initial control code fileof the (i+1)^(th) layer object.

After obtaining the combined thickness and the combined control codefile of the stack object, the processor 110 controls an irradiationpathway of the light source according to the combined control code fileto cure the irradiated liquid molding material 102, so as to form the 3Dobject on the movable platform 130 (Step S410). In other words, when theprocessor 110 moves the movable platform 130 to a position on the Z axisaccording to the combined thickness, the light source 140 irradiates andcures a portion of the liquid molding material 102 according to theadjusted output intensity and the combined control code file of thestack object. Therefore, the movable platform 130 moves along the Zaxis, and the liquid molding material 102 is gradually cured along theway to complete the formation of the 3D object 50.

For example, FIG. 5A and FIG. 5B are schematic cross-sectional diagramsillustrating a three-dimensional object according to an exemplaryembodiment. With reference to FIG. 5A and FIG. 5B, in this embodiment, a3D object includes a plurality of layer objects 5 a-5 g after theslicing process, wherein each of the layer objects 5 a-5 g has the samestandard thickness. As shown in FIG. 5A, it is given that 2D images ofthe layer objects 5 b-5 d have the same coverage, and 2D images of thelayer objects 5 e-5 f have the same coverage. Therefore, a stack object5I is obtained by stacking the layer object 5 b, the layer object 5 c,and the layer object 5 d. The combined thickness of the stack object 5Iis three times the standard thickness. A combined control code file ofthe stack object 5I is the same as the initial control code files of thelayer object 5 b, the layer object 5 c, and the layer object 5 d.

Similarly, a stack object 5J is obtained by stacking the layer object 5e and the layer object 5 f. The thickness of the stack object 5J is twotimes the standard thickness. A combined control code file of the stackobject 5J is the same as the initial control code files of the layerobject 5 e and the layer object 5 f. A stack object 5H is equivalent tothe layer object 5 a, and a stack object 5K is equivalent to the layerobject 5 g.

Based on the above, it is given that a printing direction is a directionof printing from the layer object 5 a to the layer object 5 g. After the3D printing apparatus 100 finishes printing the layer object 5 a (thestack object 5H), the 3D printing apparatus 100 only needs to increasethe output intensity of the light source 140 and move the movableplatform 130 once according to the combined thickness of the stackobject 5I to generate the stack object 5I by one scan. By contrast tothe above, if the stack object 5I is not formed by stacking, the 3Dprinting apparatus 100 has to move the movable platform 130 three timesand perform scanning three times to sequentially generate the layerobjects 5 b-5 d. It is known from the above that, by generating thestack object 5I, the printing speed of the 3D printing apparatus 100 isincreased efficiently.

FIG. 6 is a flowchart illustrating a three-dimensional printing methodaccording to an exemplary embodiment. The method of this embodiment isadapted for the 3D printing system of FIG. 1 and the 3D printingapparatus of FIG. 3. Steps of the 3D printing method of this embodimentare explained in detail hereinafter with reference to the components ofthe 3D printing system 10 and the 3D printing apparatus 100.

First, the processor 210 generates a 3D model, which may be a modelmanufactured by the user with use of model editing software or a 3Dmodel obtained by scanning an object using 3D scanning technology. Thedisclosure is not intended to limit how the 3D model is constructed orobtained. The processor 210 performs a slicing process on the 3D modelto obtain M layer objects (Step S601), wherein M is an integer greaterthan 1. Next, the processor 210 generates a plurality of initial controlcode files respectively corresponding to the layer objects (Step S602).In other words, the processor 210 generates the initial control codefile of an i^(th) layer object in sequence, wherein i is an integergreater than 0 and smaller than or equal to M. Then, the processor 210generates the 2D images of each of the layer objects according to theinitial control code files (Step S603). Steps S601-S603 are similar toSteps S401-S403 of the previous embodiment and are not repeatedhereinafter.

A difference between this embodiment and the previous embodiment is thatthe processor 210 determines whether the coverage of the 2D image of the(i+1)^(th) layer object is greater than or equal to the coverage of the2D image of the i^(th) layer object (Step S604). More specifically, theprocessor 210 determines whether the section profile of the next layerobject completely covers the section profile of the previous layerobject. If it is determined affirmative in Step S604, the processor 210adds the thickness of the (i+1)^(th) layer object to the currentcumulative thickness to generate a combined thickness (Step S605).Thereafter, the processor 210 determines whether a (i+2)^(th) layerobject exists (Step S606). If it is determined affirmative in Step S606,the processor 210 moves on to the next layer object to makedetermination (setting i=i+1) (Step S607) and repeats Step S604. It isknown from the above that layer objects that are adjacent to each otherand have coverages in an ascending order can be combined to form a stackobject. Therefore, different from the previous embodiment, the stackobject of this embodiment has a plurality of combined thicknesses, andthe combined thicknesses of this stack object are determined by thetimes of stacking and the section profile of each layer object.

On the other hand, if it is determined negative in Step S604, itindicates that the coverage of the 2D image of the (i+1)^(th) layerobject is smaller than the coverage of the 2D image of the i^(th) layerobject. That is to say, the processor 110 determines that the sectioncoverage of the next layer object is smaller than the section coverageof the previous layer object. Therefore, the processor 210 outputs aplurality of combined thicknesses of the stack object (Step S608).Moreover, the processor 210 further calculates and outputs a combinedcontrol code file of the stack object (Step S609). Specifically, theprocessor 210 obtains a plurality of combined control code files of thestack object by comparing the coverages of the layer objects.

Take the first layer object and the second layer object that areadjacent to each other as an example, if the coverage of the secondlayer object is larger than the coverage of the first layer object, theprocessor 210 adds the thickness of the first layer object to thethickness of the second layer object to generate a first combinedthickness and records the thickness of the second layer object as asecond combined thickness. Next, the processor 210 compares the coverageof the first layer object with the coverage of the second layer objectto generate a first combined control code file associated with the firstcombined thickness and a second combined control code file associatedwith the second combined thickness. That is, in this embodiment, onesingle stack object may have a plurality of combined thicknesses, whichrespectively correspond to different combined control code files. Inother words, in one single stack object, the section profiles, which arecorresponding to different combined control code files, of the stackobject and have different combined thicknesses.

Accordingly, after the processor 110 of the 3D printing apparatus 100receives the combined thicknesses and the combined control code files,the processor 110 adjusts the output intensity of the light sourceaccording to the combined thicknesses (Step S610). The processor 110controls the irradiation pathway of the light source according to thecombined control code files to cure the irradiated liquid moldingmaterial 102, so as to form the 3D object on the movable platform 130(Step S611). More specifically, when the processor 110 moves the movableplatform 130 to a position on the Z axis according to the thickest oneof the combined thicknesses, the light source 140 adjusts the outputintensity according to different combined thicknesses and irradiates andcures a portion of the liquid molding material 102 according to thecurrent adjusted output intensity and the corresponding combined controlcode files.

FIG. 7A and FIG. 7B are schematic cross-sectional diagrams illustratinga three-dimensional object according to an exemplary embodiment. FIG. 7Cis a schematic diagram illustrating obtaining a combined control codefile according to an exemplary embodiment.

With reference to FIG. 7A and FIG. 7B, in this embodiment, a 3D objectincludes a plurality of layer objects 7 a-7 c after the slicing process,wherein each of the layer objects 7 a-7 c has the same standardthickness. In this embodiment, it is given that the maximum thicknessthat the light source 140 can cure is five times the standard thickness.That is, if the output intensity of the light source 140 is 100%, thethickness that can be cured is five times the standard thickness. If theoutput intensity of the light source 140 is 60%, the thickness that canbe cured is three times the standard thickness, and so forth.

As shown in FIG. 7A and FIG. 7B, it is given that the section coveragesof the layer objects 7 a-7 c are in an ascending order. Therefore, astack object 7D is obtained by stacking the layer object 7 a, the layerobject 7 b, and the layer object 7 c. In this embodiment, because thelayer object 7 a, the layer object 7 b, and the layer object 7 c havedifferent coverages, the stack object 7D has three combined thicknesses.As shown in FIG. 7B, the stack object 7D is divided into a portion 7D_1,a portion 7D_2, and a portion 7D_3. The combined thickness of theportion 7D_1 is three times the standard thickness, the combinedthickness of the portion 7D_2 is two times the standard thickness, andthe combined thickness of the portion 7D_3 is equal to the standardthickness.

Further referring to FIG. 7C, the layer object 7 a has a coverage 7 a_(—) s corresponding to the slice plane, the layer object 7 b has acoverage 7 b _(—) s corresponding to the slice plane, and the layerobject 7 c has a coverage 7 c _(—) s corresponding to the slice plane.It is known from the above that an overlap portion of the layer object 7a, the layer object 7 b, and the layer object 7 c is an overlap coverage7D_1 s. An overlap portion of the layer object 7 b and the layer object7 c is an overlap coverage 7D_2 s. A portion of the layer object 7 cwhich does not overlap the layer object 7 a and the layer object 7 b isan overlap coverage 7D_3 s.

Accordingly, the combined thickness corresponding to the overlapcoverage 7D_1 s is three times the standard thickness. The combinedthickness corresponding to the overlap coverage 7D_2 s is two times thestandard thickness. The combined thickness corresponding to the overlapcoverage 7D_3 s is equal to the standard thickness. That is to say, thesection coverage of the portion 7D_1 corresponding to the slice plane isthe coverage 7D_1 s, the section coverage of the portion 7D_2corresponding to the slice plane is the coverage 7D_2 s, and the sectioncoverage of the portion 7D_3 corresponding to the slice plane is thecoverage 7D_3 s. Thus, combined control code files corresponding todifferent combined thicknesses are generated based on the coverages 7D_1s, 7D_2 s, and 7D_3 s.

Accordingly, it is given that the printing direction is a direction ofprinting from the layer object 7 a to the layer object 7 c. It is knownfrom the above that the 3D printing apparatus 100 only needs to move themovable platform 130 one time to generate the stack object 7D.Furthermore, the 3D printing apparatus 100 adjusts the output intensityof the light source 140 to 60% according to the combined thickness ofthe portion 7D_1 and generates the portion 7D_1 of the stack object 7Don the movable platform 130 according to the combined control code filecorresponding to the portion 7D_1. Then, the 3D printing apparatus 100adjusts the output intensity of the light source 140 to 40% according tothe combined thickness of the portion 7D_2 and generates the portion7D_2 of the stack object 7D on the movable platform 130 according to thecombined control code file corresponding to the portion 7D_2. At last,the 3D printing apparatus 100 adjusts the output intensity of the lightsource 140 to 20% according to the combined thickness of the portion7D_3 and generates the portion 7D_3 of the stack object 7D on themovable platform 130 according to the combined control code filecorresponding to the portion 7D_3. Based on the above, by generating thestack object 7D, the printing speed of the 3D printing apparatus 100 isincreased efficiently.

To sum up, in the above embodiments of the disclosure, multiple layerobjects that match the stack condition are stacked to generate the stackobject having the cumulative thickness. Accordingly, the 3D printingapparatus adjusts the output intensity of the light source according tothe cumulative thickness of the stack object and controls theirradiation pathway according to the combined control code file.Compared with a 3D printing method of printing uniform layer thickness,the embodiments of the disclosure utilize the stack object to reduce thetimes of moving the movable platform and the times of scanning of thelight source, thereby significantly improving the printing efficiency ofthe 3D printing apparatus.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the disclosed embodimentswithout departing from the scope or spirit of the disclosure. In view ofthe foregoing, it is intended that the disclosure covers modificationsand variations provided that they fall within the scope of the followingclaims and their equivalents.

What is claimed is:
 1. A three-dimensional printing method, adapted forprinting a three-dimensional object, the three-dimensional printingmethod comprising: obtaining a plurality of layer objects of athree-dimensional model and generating a plurality of two-dimensionalimages, corresponding to a slice plane, of each of the layer objects,wherein the layer objects comprise a first layer object and a secondlayer object adjacent to each other; stacking the first layer object andthe second layer object to generate thickness stack information of astack object when a comparison relationship between the two-dimensionalimage of the first layer object and the two-dimensional image of thesecond layer object matches a stack condition; and initiating a printingmechanism according to the thickness stack information to print thethree-dimensional object associated with the three-dimensional model. 2.The three-dimensional printing method according to claim 1, wherein thestep of obtaining the layer objects of the three-dimensional model andgenerating the two-dimensional images, corresponding to the slice plane,of each of the layer objects comprises: performing a slicing process onthe three-dimensional model to obtain the layer objects; generating aplurality of initial control code files respectively corresponding tothe layer objects; and generating the two-dimensional images of each ofthe layer objects according to the initial control code files.
 3. Thethree-dimensional printing method according to claim 1, wherein theinitial control code files are G code files.
 4. The three-dimensionalprinting method according to claim 1, wherein the step of stacking thefirst layer object and the second layer object to generate the thicknessstack information of the stack object when the comparison relationshipbetween the two-dimensional image of the first layer object and thetwo-dimensional image of the second layer object matches the stackcondition comprises: stacking the first layer object and the secondlayer object to generate at least one combined thickness and at leastone combined control code file of the stack object when a coverage ofthe two-dimensional image of the second layer object is larger than orequal to a coverage of the two-dimensional image of the first layerobject.
 5. The three-dimensional printing method according to claim 4,wherein the step of stacking the first layer object and the second layerobject to generate the at least one combined thickness and the at leastone combined control code file of the stack object when the coverage ofthe two-dimensional image of the second layer object is larger than orequal to the coverage of the two-dimensional image of the first layerobject comprises: determining whether the coverage of thetwo-dimensional image of the second layer object is equal to thecoverage of the two-dimensional image of the first layer object; and ifaffirmative, adding a thickness of the first layer object and athickness of the second layer object to generate the at least onecombined thickness.
 6. The three-dimensional printing method accordingto claim 5, further comprising: setting the at least one combinedcontrol code file as an initial control code file of the second layerobject, wherein the initial control code file of the second layer objectis the same as an initial control code file of the first layer object.7. The three-dimensional printing method according to claim 4, whereinthe step of stacking the first layer object and the second layer objectto generate the at least one combined thickness and the at least onecombined control code file of the stack object when the coverage of thetwo-dimensional image of the second layer object is larger than or equalto the coverage of the two-dimensional image of the first layer objectcomprises: determining whether the coverage of the two-dimensional imageof the second layer object is larger than the coverage of thetwo-dimensional image of the first layer object; and if affirmative,adding the thickness of the first layer object and the thickness of thesecond layer object to generate a first combined thickness of the atleast one combined thickness and recording the thickness of the secondlayer object as a second combined thickness of the at least one combinedthickness.
 8. The three-dimensional printing method according to claim7, further comprising: comparing the coverage of the first layer objectwith the coverage of the second layer object to generate a firstcombined control code file associated with the first combined thicknessand a second combined control code file associated with the secondcombined thickness.
 9. The three-dimensional printing method accordingto claim 4, wherein the step of initiating the printing mechanismaccording to the thickness stack information to print thethree-dimensional object associated with the three-dimensional modelcomprises: adjusting output intensity of a light source according to theat least one combined thickness; and controlling an irradiation pathwayof the light source according to the at least one combined control codefile to cure an irradiated liquid molding material, so as to form thethree-dimensional object on a movable platform.
 10. Thethree-dimensional printing method according to claim 1, wherein theprinting mechanism is a stereolithography (SLA) printing mechanism. 11.A three-dimensional printing apparatus, comprising: a processorobtaining a plurality of layer objects of a three-dimensional model andgenerating a plurality of two-dimensional images, corresponding to aslice plane, of each of the layer objects, wherein the layer objectscomprise a first layer object and a second layer object adjacent to eachother, and the processor stacks the first layer object and the secondlayer object to generate thickness stack information of a stack objectwhen a comparison relationship between the two-dimensional image of thefirst layer object and the two-dimensional image of the second layerobject matches a stack condition, wherein the processor initiates aprinting mechanism according to the thickness stack information to printa three-dimensional object associated with the three-dimensional model.12. The three-dimensional printing apparatus according to claim 11,wherein the processor obtains a plurality of initial control code filesrespectively corresponding to the layer objects from an electronicapparatus and generates the two-dimensional images of each of the layerobjects according to the initial control code files.
 13. Thethree-dimensional printing apparatus according to claim 11, wherein theprocessor stacks the first layer object and the second layer object togenerate at least one combined thickness and at least one combinedcontrol code file of the stack object when a coverage of thetwo-dimensional image of the second layer object is larger than or equalto a coverage of the two-dimensional image of the first layer object.14. The three-dimensional printing apparatus according to claim 13,wherein the processor determines whether the coverage of thetwo-dimensional image of the second layer object is equal to thecoverage of the two-dimensional image of the first layer object; and ifaffirmative, the processor adds a thickness of the first layer objectand a thickness of the second layer object to generate the at least onecombined thickness.
 15. The three-dimensional printing apparatusaccording to claim 14, wherein the processor sets the at least onecombined control code file as an initial control code file of the secondlayer object, wherein the initial control code file of the second layerobject is the same as an initial control code file of the first layerobject.
 16. The three-dimensional printing apparatus according to claim13, wherein the processor determines whether the coverage of thetwo-dimensional image of the second layer object is larger than or equalto the coverage of the two-dimensional image of the first layer object;and if affirmative, the processor adds the thickness of the first layerobject and the thickness of the second layer object to generate a firstcombined thickness of the at least one combined thickness and recordsthe thickness of the second layer object as a second combined thicknessof the at least one combined thickness.
 17. The three-dimensionalprinting apparatus according to claim 16, wherein the processor comparesthe coverage of the first layer object with the coverage of the secondlayer object to generate a first combined control code file associatedwith the first combined thickness and a second combined control codefile associated with the second combined thickness.
 18. Thethree-dimensional printing apparatus according to claim 11, furthercomprising: a container adapted for containing a liquid moldingmaterial; a movable platform disposed movably above the container; and alight source disposed under the container for irradiating the liquidmolding material, wherein the processor adjusts output intensity of thelight source according to the at least one combined thickness andcontrols an irradiation pathway of the light source according to the atleast one combined control code file to cure the irradiated liquidmolding material and form the three-dimensional object on the movableplatform.
 19. An electronic apparatus, comprising: a processor obtaininga plurality of layer objects of a three-dimensional model and generatinga plurality of two-dimensional images, corresponding to a slice plane,of each of the layer objects, wherein the layer objects comprise a firstlayer object and a second layer object adjacent to each other, and theprocessor stacks the first layer object and the second layer object togenerate thickness stack information of a stack object when a comparisonrelationship between the two-dimensional image of the first layer objectand the two-dimensional image of the second layer object matches a stackcondition, wherein the processor controls a three-dimensional printingapparatus to initiate a printing mechanism according to the thicknessstack information to print a three-dimensional object associated withthe three-dimensional model.
 20. The electronic apparatus according toclaim 19, wherein the processor performs a slicing process on thethree-dimensional model to obtain the layer objects, and generates aplurality of initial control code files respectively corresponding tothe layer objects and generates the two-dimensional images of each ofthe layer objects according to the initial control code files.